Within some computing systems, integrated circuits (e.g., processors and memory devices) may have a need to interact with each other, even though the integrated circuits may be physically located on different printed circuit boards. A technique to communicatively couple integrated circuits that are on different boards has been proposed by Rambus, Inc. of Mountain View, Calif. The “Direct RAC Data Sheet,” dated Aug. 7, 1998 how a Direct Rambus™ ASIC Cell (Direct RAC) module may be used to control the transmission of data between a processor and a memory module. See also, “Direct Rambus Clock Generation Validation” version 1.0, July 1999, available at http://www.rambus.com.
The processor may include a RAC module that controls communication over a Rambus Channel that may comprise a plurality of lines. In the Rambus specification, each line in the Rambus Channel has an impedance value of 28 Ohms. The specification also provides for the use of connectors to connect a memory module to a printed circuit board containing a processor. However, the currently available connectors that may be used to connect memory modules to the Rambus Channel place the memory module at a right angle relative to the channel. Consequently, the memory modules extend at a right angle from the printed circuit board that contains the processor.
Although this configuration may be well suited to desktop applications, conventional implementations in accordance with the Rambus specification are not well suited for applications that have small form factors, for example, portable computing applications. Moreover, the current Rambus specification specifies that the Rambus Channel is to have an impedance value of 28 Ohms. This specification may impose a limitation on the number of memory modules or repeater hubs that may be coupled to the Rambus Channel due to fan-out issues.
Thus, there is a continuing need for better ways to communicatively couple processors to memory modules.
It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.